Android/iOS: Photo filters can give your pictures an interesting look, but most apps tend to only have a dozen or so to choose from. Shift lets you adjust and randomise a virtually limitless number of photos and save them for later.
The app uses very simple controls to adjust where on the photo the filter is applied, as well as the intensity or hue. You can tap the randomize button to get a new starting point and adjust as needed. When you find a look you like, you can give it a name and save it for later.
Shift (Free) [Google Play Store]
Shift ($1.29) [iTunes App Store]